The Gl training program of the Massachusetts General Hospital (MGH) is dedicated to the preparation of investigators committed to a career in Gl biomedical research. This program continues to build on its extensive past experience in establishing productive and committed digestive diseases investigators. Fundamental features of the post-doctoral training format, the major component of this program, include direct research participation in conjunction with a comprehensive program of didactic instruction and enrichment activities to provide a deep foundation in biomedical science and modern research techniques. In addition, continuation of a two-year pre-doctoral laboratory research program is proposed to attract minority students to careers in Gl research. (A) Research Areas and Disciplines. The strength of the research base of this program encompasses a spectrum of research interests. The majority of trainees will undertake training in laboratory research in which emphasis is placed on the application of tools of molecular biology to Gl research. Training is offered in several disciplines: Molecular Biology, Biochemistry, Membrane Biology, Developmental Biology, Genetics, and Immunology. These disciplines are applied to nine research themes central to the current study of digestive diseases. For trainees undertaking training in clinical investigation, a rigorous preparation in relevant quantitative sciences, including Biostatistics and Epidemiology, is provided. (B) Level of Training. Background and Numbers of Trainees. This renewal proposes both post-doctoral and pre-doctoral training. Post-doctoral training is offered to individuals holding M.D.,M.D.-Ph.D. or relevant Ph.D. degrees. Six post-doctoral positions are requested: three post-doctoral fellows will begin training each year, and remain in research training for a minimum of two years supported by this award. In addition, two positions are requested to continue the pre-doctoral training fellowship for minority students completing an undergraduate degree or enrolled in graduate or medical school, one student entering each year for a 1-2 year period. (C) Training Facilities. Research training will take place in the existing laboratories of the research mentors; a group of established investigators with extensive existing interactions. Laboratories are present at the MGH, a large general hospital with more than 900,000 sq. ft. of space dedicated to research. In addition, training opportunities will be available in laboratories elsewhere in Harvard University and M.I.T. Didactic educational programs will include those offered through the Harvard Medical School, other affiliates of the Harvard Medical School, the Harvard School of Public Health, Harvard University and M.I.T.